example.test.js

const getArea = require('./area.js')

test('more than 2  array elements', () => {
    expect(getArea([2,3,4])).toBe(-1)
});

test('less than 2 array elements ', () => {
    expect(getArea([4])).toBe(-1)
});

test('one array element is null', () => {
    expect(getArea([2,null])).toBe(-1)
});

test('second array element is not a number', () => {
    expect(getArea([2,'fdfd'])).toBe(-1)
});

test('first array element is not a number', () => {
    expect(getArea(['fdfd',2])).toBe(-1)
});

test('correct area computation', () => {
    expect(getArea([2,3])).toBe(6)
});

test('correct area computation with zeros', () => {
    expect(getArea([0,3])).toBe(0)
});

test('one parameter is not an integer', () => {
    expect(getArea([2.5,2])).toBe(-1)
});

test('one parameter is a string that is a number', () => {
    expect(getArea(['1',2])).toBe(-1)
});


test('one parameter is undef', () => {
    expect(getArea([0,])).toBe(-1)
});

test('parameter is an object', () => {
    expect(getArea({a:1,b:2})).toBe(-1)
});

test('negative integers', () => {
    expect(getArea([-2,6])).toBe(-1)
});

test('no pars', () => {
    expect(getArea()).toBe(-1)
});

test('two pars instead of one', () => {
    expect(getArea([2,3],5)).toBe(-1)
});